Bash script embedded TMSH command can't execute.

I've just tried it on my box and it worked:

[root@default:/S1-green-P:Active:Standalone] config  tmsh list /net self
net self 192.168.0.1 {
    address 192.168.0.1/30
    traffic-group traffic-group-local-only
    vlan Xover
}
net self 172.31.19.231 {
    address 172.31.19.231/23
    allow-service all
    traffic-group traffic-group-local-only
    vlan IN
}

[root@default:/S1-green-P:Active:Standalone] config  tmsh delete net self 192.168.0.1

[root@default:/S1-green-P:Active:Standalone] config  tmsh list /net self
net self 172.31.19.231 {
    address 172.31.19.231/23
    allow-service all
    traffic-group traffic-group-local-only
    vlan IN
}

Can you show output of

list /net self